The objective of this project is to bridge a gap between basic research on the neurophysiology of vision and clinical research on visual disorders. To this end we have constructed two microcomputer-based visual stimulator/data analyzers specially designed for use as diagnostic instruments. The basic method--recording, from the scalp, evoked potentials produced by patterned stimuli--is one of the simplest that can be used to study human vision. But by using a sophisticated approach this simple method can provide a powerful tool. The instruments utilize versatile and up to date electro-optical displays of our own design for visual stimulation. The instruments display a variety of two-dimensional spatio-temporal patterns for the study of spatial interactions. These spatial patterns may be temporally modulated by an arbitrary voltage signal including a sum-of-sinusoids closely related to (but simpler than) the Wiener white noise. For the data reduction many standard mathematical methods of linear systems analysis are used. Most important, however, is a novel, more efficient version of Wiener analysis of both linear and nonlinear systems recently developed in our laboratory. The methods of stimulation and of data analysis have been thoroughly tested in extensive basic research in lower animals (including some with visual deficits) and in some pilot experiments on humans with normal vision. By bringing versatile and well controlled visual stimulators and rigorous and powerful analytic methods into the clinical laboratory we hope to advance our understanding of normal human vision and of pathologies of the visual pathway from the eye to the cortex.